My take includes a little from what both George and Matt said.
I think the “repeated zooming and circling” phrase referred to one spot on the island. A specific location where there were “signs of recent habitation”. The suspected Camp Zero after it was abandoned. Just based on I don’t think it would be described as “zooming” if you went around the whole island.
A separate big search circle around the island and one around the lagoon makes sense to me if they had time. Lambrecht noted the lagoon as a possible landing area when he noted “Given a chance, it is believed that Miss Earhart could have landed her plane in this lagoon and swam or waded ashore”
As far as moving to where she saw planes, or if AE even heard or saw these planes, she may have gone to the shore already searched and was blocked from view by trees when they searched the other shore.
The shape of the island is like searching two. An inner island and an outer island
Worst case for trying to be seen could be moving back and forth between the shores, always chasing where they were